The present invention relates to a system and method for supporting a lane tracking travel of a vehicle, and more particularly to a lane tracking control system which determines whether a vehicle tends to depart from a lane according to a vehicle traveling condition on the lane and which controls a lane departure distance or time when the vehicle departs from the lane.
Japanese Patent Provisional Publication No. 11-348697 discloses a lane tracking control system which is arranged to generate alarm when the vehicle departs from a traveling lane.
However, this earlier control system generates alarm with little margin time when a vehicle travels a curved road and when a driver is not steering the vehicle. This little margin time is not sufficient for the driver to execute a steering operation for correcting a traveling locus of the vehicle so as to travel the vehicle within the traveling lane.
It is therefore an object of the present invention to provide a lane tracking control system which accurately detects a lane departure tendency of the vehicle and which controls the vehicle so as to ensure a margin time during when a driver easily executes a steering operation for correcting a traveling locus of the vehicle.
An aspect of the present invention resides in a lane tracking control system for a vehicle, which comprises a road image detector taking a view ahead of the vehicle; a vehicle behavior detector detecting a behavior of the vehicle; a steering control mechanism executing a steering control in response to a steering control signal; and a controller coupled to the road image sensor, the vehicle behavior detector and the steering control mechanism. The controller is arranged to calculate a road shape on the basis of the view taken by the road image detector, to determine whether the vehicle tends to depart from a lane traveled by the vehicle, on the basis of the road shape and the vehicle behavior detected by the vehicle behavior detector, and to output the steering control signal to the steering control mechanism to control the vehicle behavior at a desired behavior when the vehicle tends to depart from the lane.
Another aspect of the present invention resides in a method for tracking a lane traveled by a vehicle, which comprises a step of taking a view ahead of the vehicle; a step of detecting a behavior of the vehicle; a step of calculating a road shape on the basis of the view taken by the road image detector, a step of determining whether the vehicle tends to depart from the lane traveled by the vehicle, on the basis of the road shape and the vehicle behavior; and a step of outputting a control signal to a steering control mechanism for steering the vehicle to control the vehicle behavior at a desired behavior when the vehicle tends to depart from the lane.